Question

The pair in which both species have same magnetic moment (spin only value) is

• A. $\left[ Cr \left( H _{2} O \right)_{6}\right]^{2+},\left[ CoCl _{4}\right]^{2-}$
• B. $\left[ Cr \left( H _{2} O \right)_{6}\right]^{2+},\left[ Fe \left( H _{2} O \right)_{6}\right]^{2+}$
• C. $\left[ Mn \left( H _{2} O \right)_{6}\right]^{2+},\left[ Cr \left( H _{2} O \right)_{6}\right]^{2+}$
• D. $\left[ CoCl _{4}\right]^{2-*},\left[ Fe \left( H _{2} O \right)_{6}\right]^{2+}$

Answer 1

The Correct Option is B

$\left[ Cr \left( H _{2} O \right)_{6}\right]^{2+}= Cr ^{2+}=3 d ^{4}=$ four unpaired electrons $\left[ CoCl _{4}\right]^{2-}= Co ^{2+}=3 d ^{7}=3$ unpaired electrons $\left[ Fe \left( H _{2} O \right)_{6}\right]^{2+}= Fe ^{2+}=3 d ^{6}=4 $ unpaired electrons $\left[ Mn \left( H _{2} O \right)_{6}\right]^{2+}= Mn ^{2+}=3 d ^{5}=5 $ unpaired electrons So, $\left[ Cr \left( H _{2} O \right)_{6}\right]^{2+}$ and $\left[ Fe \left( H _{2} O \right)_{6}\right]^{2+}$ has same magnetic moment.